Wimbledon Day 4 preview: Serena, Novak Djokovic look to restore order

Will Serena be the next star to suffer an upset at Wimbledon? She faces Caroline Garcia. (Julian Finney/Getty Images)

WIMBLEDON, England – Here are the storylines and matches to watch on Day 4 of Wimbledon. Play begins at 6:30 a.m. ET, and ESPN2 starts its coverage at 7 a.m. Click here for the order of play.

Storylines

Novak Djokovic and Serena Williams need to restore order: After Day 3 saw Roger Federer, Maria Sharapova, Victoria Azarenka and Jo-Wilfried Tsonga bite the dust, the world No. 1s would do themselves and the tournament a favor by taking care of business. Djokovic mets 156th-ranked Bobby Reynolds of the United States (third match, Centre Court). Williams will open play on No. 1 Court against Caroline Garcia, whom Serena beat 6-1, 6-2 at the French Open.

Kimiko Date-Krumm is one for the ages: The 42-year-old, a semifinalist 17years ago, plays 87th-ranked Alexandra Cadantu of Romania in the first match on Court 12. A win would match her third-round run at the Australian Open this year. That would be quite a result for Date-Krumm, who took a 12-year break from the tour between 1996 and 2008 and has returned with a renewed sense of passion. "When I was young, I always practice, train, I need to win, I want to be the top 10," she told reporters after her first-round win. "Always I had the pressure. So I didn't enjoy much when I was young. And then after, when I come back, I'm enjoying it very much, even [when] I'm losing. Of course, after losing, I'm always very disappointed. But still I'm enjoying it very much. ... I like the challenge because it's not easy for my age."

Madison Keys and Laura Robson try to keep the teenage dream alive: Keys won her Wimbledon debut, a straight-set victory over Heather Watson, and now the 18-year-old American will face No. 30 Mona Barthel, whom she beat two weeks ago in Birmingham, England. Robson, 19, already scored a big scalp with a straight-set takedown of No. 10 Maria Kirilenko. The British No. 1 will try to avoid a letdown against Mariana Duque-Marino, a Colombian qualifier ranked No. 117. Both are trying to join fellow teens Monica Puig and Genie Bouchard in the third round. After years of seeing the tour devoid of talented teens, is this the year the future arrives?

Matches to watch

James Blake vs. Bernard Tomic (second match, Court 18): Tomic retired from his doubles match on Wednesday, citing a hamstring injury, but it's possible the move was precautionary, given the slippery footing around the grounds and his five-set win over Sam Querrey in the first round. Tomic complained of dizziness during his opener (he says he didn't eat a big enough breakfast) and may not come into this match fully fit. Blake, on the other hand, routed Thiemo de Bakker 6-1, 6-3, 6-2 in the first round. But if Tomic is healthy and can work to keep the ball out of Blake's aggressive hitting zone, this should be a straightforward win.

Simona Halep vs. No. 6 Li Na (first match, No. 3 Court): Upset alert: Li draws one of the WTA's hottest players in Halep, who has won 11 consecutive matches and collected titles in Nuremberg, Germany and Rosmalen, the Netherlands, over the last two weeks. Halep is brimming with confidence, though she was taken to three sets in the first round by Olga Govortsova. Halep hasn't beaten a top-10 player during her streak. She defeated Li at the 2011 U.S. Open in their only meeting. Li is vulnerable here, as she still needs a few more matches on grass to get comfortable.

No. 23 Sabine Lisicki vs. Elena Vesnina (first match, No. 2 Court): Lisicki tends to be at her best at Wimbledon, but she should get a good test from Vesnina, who made Eastbourne her second title of the year. Lisicki leads 2-1, but they haven't played since 2009.

Kaia Kanepi vs. No. 7 Angelique Kerber (court to be announced): Kanepi is unseeded, but she's a former Wimbledon quarterfinalist who can knock off anyone if her game is clicking. Kerber is coming off a straight-set victory over Bethanie Mattek-Sands.